The overall aim of this FIRST award proposal is to study the motor coordination of neurologically normal children (3 to 9-year-olds) and adults in order to (a) assess the form and stability of certain interlimb tasks, (b) investigate the relationship between developing organismic and task constraints in modulating interlimb coordination and (c) provide a comparison to the learning disabled subpopulation with motor problems. The ability to coordinate one's limbs requires complex interaction of sensory/cognitive/motor processes; therefore, it is viewed as an indicator of neurological status. Although much research has occurred on the acquisition of interlimb skills in infancy, little work has been done in the childhood years. More importantly, almost no work has focused on multilimb coordination which would provide the best test of hemispheric interaction. Using the contemporary dynamical systems approach to motor behavior, this project will address this gap. Specifically, three tasks requiring either gross or fine motor interlimb coordination will be assessed in terms of their form, stability and flexibility over a developmental time period. At the same time, the ability to regulate biomechanical and task constraints will be determined and the effects of practice explored. Both clinicians and educators would benefit from a more complete understanding of the interaction between the developing nervous system and other constraints. Eighty subjects will participate in the initial study (sixteen each of 3-, 5-, 7-, 9-year-olds and adults). The tasks are (1) quadrupedal crawling which assesses multilimb coordination in achieving a single task, (2) walking and clapping which assesses multilimb coordination in which the two limb girdles are doing different tasks and (3) bimanual finger tapping which assesses coordination between distal contralateral pathways compared to the proximal contralateral and ipsilateral pathways of the gross motor tasks. The use of these different tasks on the same subject population will provide converging evidence related to the development of interlimb coordination. A subsequent study will investigate the same coordination properties in a population of 16 learning disabled individuals who exhibit motor problems.